The instant invention relates to vehicles having means permitting manual loading and unloading under conditions that are convenient and safe.
In order to make it possible to load and unload a vehicle under favourable safety conditions it is often desirable for all the objects to be capable of being placed on the loading platform or of being removed therefrom in such a way that the person entrusted with this activity is able to remain on one side of the vehicle only.
Examples of such vehicles are those which are used on highways and other major traffic arteries such as expressway for carrying road signs used during the setting up of road works. The placing of such signs has to be effected before the traffic has slowed down, with the result that vehicles needing to be unloaded on the left hand side of the latter (assuming that traffic normally drives on the right) expose the workers to very great accident risks. It should be noted that it is generally impossible to unload on the right on highways due to the metal safety barrier which usually borders such roads, assuming the vehicle generally drives along the emergency lane thereof.
On average, for a typical repair site, a minimum of about twenty-five signs are needed, which it would be difficult to load one next to the other in order to enable them to be unloaded directly from the back of the vehicle since, under such conditions, the latter would have to be prohibitively wide. A solution of this kind is proposed in French application No. 2 037 010. Moreover, in this case the signs must be of a specific type and placed on edge in slides fitted to the top and bottom of the trailer. There is a limit to the thickness of the signs and it is in particular impossible to provide traffic lights mounted on the signs. Moreover, in order to load or unload, the signs have to be manipulated in order to place them upright or on edge. It is also possible to arrange two rows on the base of the vehicle, namely one row in front and one behind, the front row then having to be unloaded from the side and the back row from the back of the vehicle. The above-mentioned risk is thus also present with this earlier proposal.
French application No. 2 264 683 discloses a trailer in which the signs are arranged side by side in channels which may be unloaded from the rear. Each channel contains various signs with the result that, in order to unload a sign located at the front it is first of all necessary to unload the one behind it which is at the back. This renders it necessary to load up in a specific order, which makes things additionally complicated for the workers.
Another solution is described in European application No. 0 012 705 which related to a vehicle on the loading platform of which is mounted a bracket having crossed arms on which the signs are suspended in mutually perpendicular positions.
Thus, in the case of the above-mentioned French application No. 2 264 683 the safety of the personnel is ensured since all the signs are unloaded from the rear, but this does not apply in the case of the vehicle disclosed in European application No. 0 012 705 with regard to the unloading of signs suspended on the arm of the bracket which extends in a direction transverse to the vehicle.
It is an object of the instant invention to provide a transportation vehicle for objects capable of being loaded or unloaded on one side of the vehicle only, allowing for the necessary conditions of safety and convenience, notably in its application to a transportation vehicle for road signs.
It is a further object of the instant invention to provide a transportation vehicle for objects wherein the loading height is the same for all the signs.
It is a further object of the instant invention to provide a transportation vehicle for objects wherein the signs are arranged in an upright position.
It is a further object of the invention to provide a transportation vehicle wherein the trolleys can be removed from and replaced on the trailer with the aid of a lever device when they are laden with signs; whereby a trailer may thus be very rapidly prepared for a given site.
It is a further object of the instant invention to provide a transportation vehicle for objects wherein it is possible to accommodate all types of signs in current use, including their folding support stands.
It is a further object of the instant invention to provide a transportation vehicle for objects wherein the racks may be sufficiently wide to take signs incorporating flashing signs and/or traffic lights.